Apparatus for purification of gas

ABSTRACT

A perforated cylinder having a plurality of unit perforated cylinders arranged in series and having a pair of upper and lower slits formed in the tangential direction in the sidewall. The upper portion of the cylinder is sealed and the lower portion is opened. A gas charging chamber having a gas feed pipe and a liquid feed pipe is provided at the outside bottom of the first unit cylinder. A gas-liquid separation chamber having a cleaned gas discharge pipe and a separated liquid discharge pipe is located towards the top of the last unit cylinder. Gas-liquid separation chambers having separated liquid discharge pipes are provided at the top of the cylinder in the center and at the outside of the next stage cylinder and gas passages are provided at the outside of the perforated cylinders located between said two chambers and a liquid feed pipe is connected to the bottom of the unit perforated cylinder in the middle.

[ 51 Mar. 28, 1972 6 1; Unite States atent Miura [54] APPARATUS FORPURIFICATION OF GAS [ 72] Inventor: Mitsugi Miura, 2-Chome Tezukayama,Su-

muyoshi-ku, Osaka, Japan [22] Filed: Mar. 30, 1970 [21] Appl. No.123,563

[52] [1.5. CI ..55/237, 55/455, 55/460, 55/D1G. 22, 261/79 A [51] Int.Cl ..B01d 47/10 [58] Field of Search ..55/235-239, 455, 55/D1G. 22, 89,92, 96, 460; 261/79 A [56] References Cited UNITED STATES PATENTS1,783,813 12/1930 Schneible ..55/238 1,818,742 8/1931 Paradise ..55/238X 2,560,072 7/1951 Bloomer ..55/237 X 3,028,151 4/1962 Kittle 261/79 A X3,566,582 3/1971 Yankura ..55/238 X Primary Examiner-S. Leon BashoreAssistant ExaminerRobert L. Lindsay, Jr. AttorneyGeorge B. Oujevolk [57]ABSTRACT A perforated cylinder having a plurality of unit perforatedcylinders arranged in series and having a pair of upper and lower slitsformed in the tangential direction in the sidewall. The upper portion ofthe cylinder is sealed and the lower por tion is opened. A gas chargingchamber having a gas feed pipe and a liquid feed pipe is provided at theoutside bottom of the first unit cylinder. A gas-liquid separationchamber having a cleaned gas discharge pipe and a separated liquiddischarge pipe is located towards the top of the last unit cylinder.Gasliquid separation chambers having separated liquid discharge pipesare provided at the top of the cylinder in the center and at the outsideof the next stage cylinder and gas passages are provided at the outsideof the perforated cylinders located between said two chambers and aliquid feed pipe is connected to the bottom of the unit perforatedcylinder in the middle.

6 Claims, 8 Drawing Figures Patented March 28, 1972 3,651,619

2 Sheets-Sheet 1 INVENTOR ATTORNEY 1N VEN TOR ATTORNEY APPARATUS FORPURIFICATION OF GAS This invention relates to a method and apparatus foreffectively removing fine particle solid substance such as dust, fumesor the like, contained in air or other gases, treating sulfurous acidgas, nitric acid gas, nasty odors or the like, and absorbing orneutralizing gases produced during chemical processes. Moreparticularly, it relates to a method and apparatus for obtaining cleanedgases, wherein the gas to be treated is charged into a cylinder throughlower slits of a cylinder having a set of upper and lower slits formedin the tangential direction in the side wall thereof, and a liquid atthe bottom of said cylinder is drawn by the whirling and ascending forceof the gas to cause it to rise in the form of liquid film along theinner wall of the cylinder, which liquid is then atomized by the gasentering from the slits, thus centrifugally separating the liquidcontaining impurities due to the whirling force of the gas when the gasis discharged from the upper slits.

Many methods as described below are well known for removing dust,sulfurous acid gas, etc.: (a) method, wherein a gas is brought intocontact with a liquid by sending the gas upward from the bottom of atower at a low speed and dropping atomized liquid droplets from anozzle; (b) method, wherein a gas is passed upward from the bottom of atower at a low speed and is brought into contact, on its way, with aliquid which has wetted the surface of thick-layer packing such asRaschig ring or the like; (c) method, wherein a gas is brought intocontact with water droplets obtained by mechanically splashing waterover a gas passage; (d) method, wherein a gas is sent into a liquid orto the surface of liquid at a high speed to splash the liquid by airvelocity and the liquid droplets thus obtained is brought into contactwith the gas; (e) method, wherein a gas is brought into contact withliquid by passing the gas through a layer of wire nets which areprovided in a gas passage and wetted by the liquid; (f) method, whereina gas is brought into contact with liquid by passing the gas through anarrow throat at a high speed and by violently spraying the liquidsupplied onto the throat.

These methods, known as wet dust collecting methods, are

widely used. However, in the method (a), the liquid disperses in aconical pattern, and therefore dust present in the central portion aswell as between liquid lines is not brought into contact with liquidsufficiently. In the method (b), the gas passing along the wetted wallsurface is brought into contact with liquid but the gas passing adistance from the wall surface is not brought into contact. Moreover, inthe methods (a), (b), (c), (d) and (e), channeling phenomenon is caused,whereby the gas and liquid pass through places providing least resistance, respectively, that is, they select and pass through the mosteasily passable paths. Consequently, the distribution of liquid inrelation to gas differs from place to place, and therefore uniformcontact of gas with liquid is not obtained. In addition, the methods (a)and (b) are based on the principle that dust collection is carried outby collision of falling liquid droplets and the dust contained in therising gas. If the ascending speed is high, the liquid droplets cannotfall. The ascending speed must therefore be decreased to less than 1m./sec. Thus, since the relative velocity of the dust in the gas withrespect to the liquid is low, the inertia force of the dust is small,and therefore the dust makes a detour around the liquid dropletstogether with the air current. As a result, the rate of collision withthe liquid droplets due to inertia is decreased.

In the conventional methods, as the rate of the contact between the gasand liquid is bad, the liquid must be supplied repeatedly in order toimprove the collection rate and gas removing rate and therefore theamount of liquid used is increased. In other words, the conventionalmethods are disadvantageous in that water drainage is increased.

Well known is the method wherein the gas is passed tangentially into acylinder through the charging slits and the liquid at the bottom of atank is drawn upward along the inner wall of the cylinder by utilizingthe whirling and ascending force of the gas, and the liquid so drawninto the cylinder is atomized by the gas entering the cylinder. Theconventional apparatus for achieving this method, however, is providedwith only the charging zone having charging slitz and is not providedwith the exhaust zone having exhaust slits, and the top of the cylinderis left opened. Consequently, it is observed that the greater part ofthe ascending gas is not forcibly exhausted through exhaust slits undercentrifugal force as in the present invention but instead risesdirectly, through the center of the cylinder and therefore carries withit the floating droplets. Therefore, it is necessary to provide a mistseparator. Even with such an apparatus in which the top of cylinder isopened, the efficiency of dust removal and gas separation can beincreased, if the cylinders are stacked in several stages. In thisapparatus, however, liquid is separated at each stage, and therefore itis necessary to supply another liquid to the next stage and the amountof liquid used increases. In addition, if the gas discharged into agas-liquid separation chamber of large diameter with weakened whirlingforce is admitted into a liquid feed pipe at the next stage, thewhirling motion is disturbed, thus producing turbulence and increasingpower costs.

A principal object of this invention is to provide a method andapparatus for effectively removing impurities contained in gas byeffectively bringing gas into contact with a small quantity of liquidatomized and dispersed into the gas to be treated.

Another object of this invention is to provide a method and apparatusfor obtaining cleaned gas through centrifugal separation by circlinggas.

The preferred embodiments of this invention are described below, whichshould be read in conjunction with the accompanying drawings in which:

FIG. 1 is a front cross-sectional view of an embodiment of the unit gasprocessing apparatus according to this invention;

FIG. 2 is a cross-sectional view taken on the line IIlI of FIG. 1;

FIG. 3 is a cross-sectional view taken on the line IIIIII of FIG. 1;

FIGS. 4 and 5 are front sectional view, respectively, illustratingembodiments of compound gas processing apparatus according to thisinvention;

FIG. 6 is a front cross-sectional view of a gas processing apparatuswherein perforated cones are used instead of perforated cylinders;

FIG. 7 is a cross-sectional view taken on the line VII-VII of FIG. 6;and

FIG. 8 is a cross-sectional view taken on the line VIIIVIII of FIG. 6.

Referring to FIGS. 1, 2 and 3, the numeral 1 indicates a gas feed pipe.The numeral 2 indicates a gas charging chamber, at the bottom of which aliquid tank 3 is provided. Above the gas charging chamber 2 is providedan outer drum 4, above which is provided a gas-liquid separation chamber5. A perforated cylinder 6 is provided inside the outer drum 4.

The perforated cylinder 6 consists of a plurality of unit perforatedcylinders 11 which are successively placed one upon another. Each of theunit perforated cylinders 11 comprises a charging portion 8 and adischarge portion 10. The charging portion 8 is provided with aplurality of gas charging slits 7 which are opened in the tangentialdirection of the side wall of the cylinder. The discharge portion 10 isprovided with a plurality of gas discharge slits 9 which are opened inthe tangential direction of the side wall of the cylinder. (Shown inFIG. I are three unit perforated cylinders connected in series.) Theseunit perforated cylinders 11, are of bottom opening type and their topsare sealed by means of partition plates 12. The doughnut-shaped spaceformed by the outer drum 4 and the unit perforated cylinders 11, isdivided by means of division plates l5, l6 and 17 into a gas chargingchamber 2, gas passages 13 and 14 and a gas-liquid separation chamber 5.The division plates 15, 16 and 17 are provided at the portions borderingthe charging zone and the discharge zone of the perforated cylinder. Thegas-liquid separation chamber is provided with a cleaned gas dischargepipe 18 at the top and a separated liquid discharge pipe 19 at thebottom. In addition, a liquid feed pipe 20 connected to the liquid tank3 at the bottom of the gas charging chamber 2 and a drain port 21 areprovided.

The charging slits and discharge slits formed at the side of theperforated cylinders in the tangential direction are provided indirections opposite to each other so that gas passing through willalways whirl in the same direction. For example, in FIG. 2, the gasentering the charging slits in the clockwise direction is whirledclockwise and leaves the discharge slits. Consequently, the charging anddischarging slits are provided opposite to one another as shown in FIGS.2 and 3. In this apparatus, the areas of unit perforated cylinders,slits and gas passages are designed so that the gases pass through theseopenings at a high speed.

Described below is the performance of this apparatus. When a gascontaining dust or the like is sent into the cylinder through thecharging slits, the gas is passed upward, whirling within the unitperforated cylinders at a high speed. At this time, the liquid at thebottom is drawn by the gas and forms a liquid film on the inner wall ofthe unit perforated cylinder which goes up into the discharge zonethrough the charging zone. The liquid film passing upward in thecharging zone is atomized by the gas entering from the charging slits inthe tangential direction at a high speed, is effectively mixed with thegas and is whirled at a high speed. Wetted dust, liquid droplets oruncaught dust settle on the inner wall of the charging zone due tocentrifugal force and are caught by the liquid film. The settled liquidfilm is again atomized by the entering gas. The liquid containing dustwhich is sent to the discharge zone through the charging zone isatomized by the gas which is whirled at a high speed and thendischarged. Then, this liquid is mixed with the gas. The dischargedliquid is passed upward in the gas passage, being drawn by the gaspassing upward at a high speed along the gas passage 13 having thedoughnutshaped cross section formed by the perforated cylinder 6 and theouter drum 4. This liquid finally enters the cylinder together with thegas through the charging slits of the secondstage perforated cylinder11.

The operation at the unit perforated cylinders after the first stage isdifferent from that at the first stage. The gas entering from thecharging slits is brought into contact with the liquid more effectivelythan at the first stage in order to atomize the accompanied liquiddroplets, liquid film on the outer wall of the cylinder and the liquidfilm on the inner wall of the cylinder. The gas is finally dischargedinto the gas-liquid separation chamber through the discharge zone at thefinal stage by repeating the above-described operations, that is,entering from the charging zone 8 of the first-stage unit perforatedcylinder, discharging from the discharge zone 10, ascending along thegas passage 13, entering from the charging zone 8 of the second-stageunit perforated cylinder, discharging from the discharge zone 10,ascending along the gas passage 14 and entering from the charging zone 8of the thirdstage unit perforated cylinder. The cross-sectional area ofthe gas-liquid separation chamber is large enough to allow the gasdischarged from the discharge zone to go up at low speed of 3 m./sec.and less. Therefore, the gas discharged from the slits continues to goup at a slow speed and is discharged from the cleaned gas discharge pipe18, but the liquid containing dust does not go up together with the gasbut advances at a high speed in the tangential direction towards thewall of the gas-liquid separation chamber and collapses with the wall orfalls on the way thus collecting on the bottom. Thus, effectiveseparation of gas from liquid is carried out. Therefore, this inventionenables separation of liquid containing dust or gas required to betreated by effectively utilizing high-speed whirling force of the gas.

In the apparatus of the conventional known method wherein the upper endthereof is not sealed and the exhaust zone having a exhaust slit is notprovided, there are disadvantages in that as the greater part of the gasrises directly from the opening end, the centrifugal force exerted tothe liquid of liquid film is weak and the fine liquid droplets dispersedto the center portion are difficult to separate.

On the other hand, in the present invention, the upper edge of theapparatus is sealed and all the amounts of the gas are forciblyexhausted from the exhaust slit by means of centrifugal exhaust at ahigh speed, the liquid film ascending along the inner wall isaccompanied by the exhaust gas and is subjected to centrifugalseparation at a very high speed. In addition, the fine liquid dropletsdispersed to the center portion are accompanied by the gas and reach theinner wall of the exhaust slit and thus join the ascending liquid film.Consequently, centrifugal separation can be effectively carried out, andit is unnecessary to provide a mist separator used in a general wettypedust collector.

The width of the charging and discharge slits of this invention isgenerally small and is freely changeable to 1 mm., 5 mm., 10 mm. andetc., depending on the purpose of use. The less the width of the slit,the narrower the width of the gas to flow accompanying the atomizedliquid droplets. Thus, the contact of gas with liquid is moreeffectively accomplished. Therefore, in collecting dust of super fineparticles which are generally difficult to collect, the width of theslit is decreased. In the case of large-sized particles, they are settleto and are caught by the liquid film on the inner wall of the cylinderduring the whirling motion due to centrifugal force, and therefore higheffective dust collection is effected even if the width of the slit islarge. For super fine fumes of 0.1 micron and less, efficiency can beimproved by increasing the number of stages of unit perforated cylindersin addition to the slit width control. For easily removable large-sizedparticles, satisfactory dust collecting effect can be had by the onlyone-stage perforated cylinder. In other words, the width of slits andthe number of stages of unit perforated cylinders are either increasedor decreased depending on the degree of difficulty of dust separation.

Another advantage of this invention is that the consumption of liquid isvery small, compared with conventional wet method. In this invention,the amount of liquid required is equal to the amount of liquid to bepassed upward in the form of thin film along the inner wall of the unitperforated cylinder. Even if the number of stages of unit perforatedcylinders is increased, the same liquid is passed upward, and thereforeit is not necessary to increase the amount of liquid to be used. If theconsumption of liquid decreases, the amount of liquid to be dischargeddecreases. According to the method of this invention, the amount ofliquid to be discharged is small and is about one tenth to one fiftiethof the amount required in the conventional wet method using a nozzlespray. Further, after the greater part of the dust contained in theliquid is removed by precipitation or centrifugal separation, therestill remains a small amount of the dust in the liquid. If the liquiddischarged is refluxed into the liquid tank 3 to be repeatedly used, theamount of liquid to be discharged is about 1/30 1/100 of that requiredfor the conventional method. The cost for drainage is markedly reduced.Moreover, according to this invention, the width of the opening of theslit is far larger than the size of dust contained in the liquid, andtherefore the slits are never clogged with dust contained in the liquidto be refluxed for reuse. On the other hand, in the conventional wettypedust collecting method using a nozzle, the nozzle is clogged with dustcontained in the liquid because of the small diameter thereof.Therefore, discharged liquid containing dust cannot be refluxed forreuse.

In addition, according to this invention, the amount of liquid to beused is small. Therefore, in handling a gas to be treated, absorptionliquid of high concentration is obtained.

Since the gas to be treated is whirled in the same direction accordingto this invention, pressure loss is negligible.

Described above is a method in which the same liquid is used in theperforated cylinders. This invention is applicable to the case wheredifferent kinds of liquid are used. For example, in case when a gascontains dust as well as sulfurous acid gas, dust is removed by use ofwater as the first liquid and then sulfurous acid gas is separated byusing caustic soda solution as the second liquid. In this case, acompound gas processing apparatus as shown in FIG. 4, in which a unitgas processing apparatus A and a unit gas processing apparatus B areconnected in series, is used. In this case, the gas charged from the gasfeed pipe 1 comes into contact with the water supplied from a liquidfeed pipe 22 in the unit gas processing apparatus A, where dustcontained is separated in a gas-liquid separation chamber 24. This gasis then sent into the unit gas processing apparatus B, where it comesinto contact with the caustic soda solution supplied from a liquid feedpipe 23. Then, the caustic soda solution in which sulfurous acid gas hasbeen neutralized is separated in a gas-liquid separation chamber 25 andis discharged from a discharge pipe 18. In this case, needless to say,whirling movement is continuously carried out in the same directionafter the gas enters the charging slit of the first stage and until itis discharged from the exhaust slit of the last stage.

In the drawing, only the ascending direction of the gas is shown. Thedirection is not limited to the ascending only, but the gas can beadvanced in any direction. For example, when concentrated absorptionliquid is desired to be obtained in the sulfuric acid producing process,the counter current process is possible as shown in FIG. 5. In anapparatus wherein a plurality of unit gas processing apparatus A, B andC are provided in series, the gas to be treated is passed upward in thefirst unit gas processing apparatus A, the second unit gas processingapparatus B and the third unit gas processing apparatus C successivelywhile whirling movement is kept to be performed in the same direction.On the other hand, the absorption liquid is supplied from a liquid feedpipe 28 to the bottom of the third unit gas processing apparatus. Then,the absorption liquid separated in a third separation chamber 31 issupplied from a feed pipe 27 into the second unit gas processingapparatus B. liquid separated in a second separation chamber 30 of thesecond unit gas processing apparatus B is supplied to the bottom of thefirst unit gas processing apparatus A from a liquid feed pipe 26.

If a gas to be treated is brought into contact with the absorptionliquid by counter-flowing them as described above, components to beseparated from the gas are effectively absorbed into the absorptionliquid. As a result, the concentrated absorption liquid is obtained froma first separating chamber 29.

Unit gas processing apparatus used in the compound gas processingapparatus shown in FIGS. 4 and 5 consist of two unit perforatedcylinders connected in series which are shown in FIG. 1. The number ofunit cylinders can be one or more than one, depending on the kind andnature of the gas. In the case of one cylinder, outer drums 4 providedat the outside of perforated cylinder as shown in the drawing can beeliminated. Thus, the gas charging chamber of each unit gas processingapparatus is adjacent to the gas-liquid separation chamber. In case whena plurality of unit perforated cylinders are used and liquid ofdifferent kinds are used as shown in FIG. 4, or in case when a pluralityof unit perforated cylinders are provided and the gas and the liquid areused in a countercurrent arrangement as shown in FIG. 5, the contact ofgas with liquid as described above is carried out in each unitperforated cylinder. It is needless to say that the number of unit gasprocessing apparatuses can be either increased or descreaded as occasiondemands.

Shown in FIGS. 6, 7 and 8 is another embodiment of this invention,wherein the shape of unit perforated cylinder of the unit gas processingapparatus is different from the one described above. The apparatus ofthis embodiment is so constructed that an open-ended reverse conei36having charging slits 35 at the side wall thereof is arranged in serieswith an open-ended cone 38 having discharge slits 37 at the side wallthereof, instead of using cylinders. Their respective ends are connectedto a separator 41 provided within a gas-liquid separating chamber 39. Inthe processes of charging the gas to be treated from a plurality ofslits 35 of the reverse cone 36 and discharging it from a plurality ofdischarge slits 37 of the cone 38, the gas is passed upward in whirlingmovement in the same manner as shown in FIG. 1, while the liquid filmgoing up along the wall of the cone is atomized into the gas. When thisgas is discharged from discharge slits 40 of a separator 41, the liquidcontained in the gas is separated by centrifugal force from the gas,thus permitting to obtain cleaned gas.

When the cone is used as shown in this embodiment, the angle ofdirection change of gas charged or discharged is smoother than in thecase of using perforated cylinder, and therefore pressure loss issmaller.

Described above are three embodiments of this invention, in which onekind of liquid is used in series, one kind of liquid is used incountercurrent and different kinds of liquid are used. As is seen fromthe above description, the biggest advantage of this invention is that,in all cases, the gas charged maintains its whirling motion in the samedirection until it is discharged.

As described above, this invention has many features and advantages.That is, according to this invention, the removal of fine particle solidsubstance such as dust, fumes or the like contained in gas, the removalof sulfurous acid gas, chloric acid and nasty odor constituting an airpollution source and absorption or other treatments of gas producedduring chemical processes can be effectively accomplished. Moreover,compared, with the conventional washing-tower type wet method, theseparation coefficient of dust or gas to be treated is high, consumptionof liquid is small and drainage is easily carried out. In addition,concentrated absorption liquid can be obtained.

I claim:

1. A gas purification apparatus comprising in combination:

a. an elongated vertical tower housing having defined higher, middle,and bottom sections with at least one closed curved wall at said bottomsection, a gas feed pipe (1) coupled to said bottom section by a pipeconvolution for tangentially feeding gas into said bottom section;

b. a separation tower in said housing with at least two pairs of units,said first or bottom and second units forming one pair, said third andtop or fourth units forming a second pair, said units being disposedvertically one above the other and being hollow chambers havingcylindrically or conically shaped outer walls with elongatedsubstantially vertical slits therein for the passage of gas through saidslits, each slit having a lip extending outwards from the outer wallforming a gas guide path substantially tangential to said outer wall toguide gas into or out of said slit, the lips in the first or bottom unitbeing charging lips extending outward in a direction designed tointercept the tangential gas flow fed by the gas feed pipe convolution,the lips in said second unit being discharging lips extending outward ina direction opposite from those in said first unit, the lips in thethird unit extending outwards in a direction substantially similar tothose in said first unit while the lips in said fourth or top unit againextending outwards in a direction substantially similar to that in saidsecond unit so that gas enters said first unit from said tower housing,exits from said second unit into said housing, reenters said third unitand again exits from said fourth or upper unit into said housing;

c. a liquid supply zone (3) disposed to supply liquid into said firstunit;

d. a first housing partition plate (15) separating said housing middlesection from said bottom section so that gas flowing into said bottomsection cannot go into said middle section without passing into saidseparation tower first or lower unit, but upon being discharged fromsaid second unit, passes into said middle section and a second housingpartition plate (17) similarly separating said housing middle and highersections;

e. at least one unit closure (12) between said first and second pairs ofunits preventing gas from one pair of units going to the second pair ofunits without traveling back into the housing; and,

f. a clean gas discharge pipe at the upper part of said higher section,and a liquid discharge outlet (19) at the lower part of said highersection.

2. A gas purification apparatus as claimed in claim 1, including afeedback pipe (20) from said liquid discharge outlet (19) to said liquidsupply zone (3).

3. A gas purification apparatus as claimed in claim 1, there being atleast three pairs of units all except the top and bottom unit being insaid middle section.

4. A gas purification apparatus as claimed in claim 1, said units in atleast said two pairs being conical, said pairs being formed by open endreverse cones (36, 38) connected at the

1. A gas purification apparatus comprising in combination: a. anelongated vertical tower housing having defined higher, middle, andbottom sections with at least one closed curved wall at said bottomsection, a gas feed pipe (1) coupled to said bottom section by a pipeconvolution for tangentially feeding gas into said bottom section; b. aseparation tower in said housing with at least two pairs of units, saidfirst or bottom and second units forming one pair, said third and top orfourth units forming a second pair, said units being disposed verticallyone above the other and being hollow chambers having cylindrically orconically shaped outer walls with elongated substantially vertical slitstherein for the passage of gas through said slits, each slit having alip extending outwards from the outer wall forming a gas guide pathsubstantially tangential to said outer wall to guide gas into or out ofsaid slit, the lips in the first or bottom unit being charging lipsextending outward in a direction designed to intercept the tangentialgas flow fed by the gas feed pipe convolution, the lips in said secondunit being discharging lips extending outward in a direction oppositefrom those in said first unit, the lips in the third unit extendingoutwards in a direction substantially similar to those in said firstunit while the lips in said fourth or top unit again extending outwardsin a direction substantially similar to that in said second unit so thatgas enters said first unit from said tower housing, exits from saidsecond unit into said housing, reenters said third unit and again exitsfrom said fourth or upper unit into said housing; c. a liquid supplyzone (3) disposed to supply liquid into said first unit; d. a firsthousing partition plate (15) separating said housing middle section fromsaid bottom section so that gas flowing into said bottom section cannotgo into said middle section without passing into said separation towerfirst or lower unit, but upon being discharged from said second unit,passes into said middle section and a second housing partition plate(17) similarly separating said housing middle and higher sections; e. atleast one unit closure (12) between said first and second pairs of unitspreventing gas from one pair of units going to the second pair of unitswithout traveling back into the housing; and, f. a clean gas dischargepipe at the upper part of said higher section, and a liquid dischargeoutlet (19) at the lower part of said higher section.
 2. A gaspurification apparatus as claimed in claim 1, including a feedback pipe(20) from said liquid discharge outlet (19) to said liquid supply zone(3).
 3. A gas purification apparatus as claimed in claim 1, there beingat least three pairs of units all except the top and bottom unit beingin said middle section.
 4. A gas purification apparatus as claimed inclaim 1, said units in at least said two pairs being conical, said pairsbeing formed by open end reverse cones (36, 38) connected at the base,said unit closure being between the apex of the first and second pairsof reverse cones.
 5. A gas purification apparatus as claimed in claim 4,there beiNg at least three pairs of units all except said top and bottomunits being in said middle section, said top unit being cylindrical. 6.A gas purification apparatus as claimed in claim 1, including in saidhigher section of the tower housing an inner wall at a substantialdistance from top unit slits, said higher section forming a gas liquidseparation chamber.